Fig. 269. Matonidium Goepperti (Ettings.). (A, B, ½ nat. size; C, approximately nat. size.)
Fronds pedate and apparently identical in habit with those of Matonia pectinata; ultimate segments linear, slightly falcate and bluntly pointed. Sori circular or oval, numerous, containing 15 to 20 sporangia with an oblique annulus, in two rows on the lower surface of the pinnules; indusium as in Matonia.
The English examples have so far afforded no information in regard to sporangial structure, but Schenk[883] has recognised a distinct annulus in German material. In his description of fossil plants from Lower Cretaceous rocks in California, Fontaine[884] doubtfully identifies two very small fragments as Matonidium Althausii; the evidence is, however, wholly inadequate.
Matonidium Wiesneri, Krasser[885]. [Fig. 265], A.
This Cenomanian (Cretaceous) species from Moravia appears to be identical in habit with the older type. The pinnules are larger and bear fewer sori. Krasser’s figures of the sterile pinnules show no lateral anastomosing between the secondary veins, but the small vascular network below each sorus ([fig. 265], A) is identical with that in Matonia pectinata. The indusiate sori contain about six sporangia with an oblique annulus.
The very wide geographical distribution of the Matonineae during the Mesozoic era affords a striking contrast to the limited range of the Malayan survivals.
Hymenophyllaceae.
The frequent use of the generic name Hymenophyllites as a designation of Palaeozoic ferns, more particularly in the older literature, is another instance of the undue importance which palaeobotanists have always been prone to attach to external resemblances of vegetative organs. The fragment of lamina described by Stur for the Culm Measures of Austria as Hymenophyllum waldenburgense[886] has no claim to consideration as evidence of Palaeozoic Hymenophyllaceae. On the other hand, there are a few records of fertile fronds which, though not to be accepted without reserve, are worthy of more careful examination. Some petrified sporangia described by Renault[887] from the Culm of Esnost are referred to Hymenophyllites on account of the position of the annulus, which appears to encircle about two-thirds of the circumference; it is, however, not certain that the annulus is horizontal as in the recent genus.
The Culm species Rhodea patentissima described by Ettingshausen[888] as Hymenophyllites patentissima and subsequently referred by Stur[889] to Rhodea, is regarded by these authors as closely allied to Hymenophyllum simply on the ground of the finely divided and delicate sterile fronds; another species, Rhodea moravica (Ett.), which Ettingshausen referred to Trichomanes, is compared with recent species of that genus. In neither case do we know anything of sporangial characters.